Conventional gas turbine engines generally include seal assemblies between a rotary component and a static component. During operation of the engine, the rotary component deflects (e.g., expands, contracts, etc.) as a function of radial, circumferential, and axial forces, thermal expansion/contraction, and pressure differentials. Seal assemblies are defined between rotary and static components to limit and control an amount of leakage or pressure loss between stages of the rotary component, or into the core flowpath or secondary flowpath, and to maintain desired pressure differentials. During operation of the engine, deflection of the rotary component is generally large relative to deflection of the static component, such as to enable considering the static component as non-deflected relative to the deflection of the rotary component.
However, interdigitated turbine rotor assemblies include rotary component to rotary component interfaces in which each rotary component experiences deflections different from the other rotary component. For example, an outer rotor assembly experience radial, circumferential, and axial forces different from an inner rotor assembly with which is interdigitated with the outer rotor assembly. As such, during operation of the engine, deflection of each rotary component is generally larger relative to conventional engines incorporating rotary-to-static seal assemblies. Therefore, leakages at rotary-to-rotary interfaces are generally large, such that performance and efficiency benefits of an interdigitated turbine arrangement may be substantially offset by leakages cross rotary-to-rotary interfaces.
As such, there is a need for structures for mitigating deflection and gas leakage across rotary-to-rotary component interfaces in interdigitated gas turbine engines.